Multiple position reclining chair



S p 10, 9 F. LscHLIEPI-IACKE 3,103,382

MULTIPLE POSITION RECLINING CHAIR Filed June s, 1960 4 Sheets-Sheet 1 FIG. I.

. INVENTOR. F'Q/DTJ F SCfi/L/EPHACKE BY v Sept. 10, 1963 4 Sheets-Sheet? Filed June 6, 1960 INVENTOR. F 1 2707701 F. \SCA L AEPHA CK 5 Se t. 10, 963 F. F. SCHLIEPHACKE 3,103,382

MULTIPLE POSITION RECLINING CHAIR Filed June 6, 1960 4 sheets-sheet 3 IN VEN TOR. F'R/D T/OF E SCHL lEPf/A CHE FIGS. "M

ATTORNEXS Sept. 10, 1963 F. F. SCHLIEPHACKE 3,

- MULTIPLE POSITION RECLINING CHAIR 4 Shets-Sheet 4 Filed June .6, 1960 BY m I fiTI'oRNEYS United States Patent 3,103,382 MULTlPLEPOSl'llON RECLlNlNG CHAER Fridtjof F. Schliephacke, Berlin-Schmargendorf, Germany, assignor to Anton Lorenz, Boynton Beach, Fla. Filed June 6, 1960, Ser. No. 34,299 3 (Ilaims. (Cl. 297-85) This invention relates toimprovements in adjustable reclining chairs, and more particularly to a novel and improved seat control structure for reclining chairs of the multiple position type.

The seat control structure of the present invention is particularly adapted for use in a chair of the doublemovement type wherein the seat and b ack-rest are i11- dependently mounted for movement to various inclined and reclined positions, and in which the angle therebctween varies during such reclining movement. In chairs of this type, the seat and back-rest are mounted f r movement from an upright sitting position through a first motion phase to an intermediate, tilted sitting position, and then through a second motion phase to a fully-reclined position. Such type of chair also includes a legrest and leg-rest control means operative in response to movement of the seat and back-rest to move the leg-rest to an extended leg-supporting position during the first motion phase, and to maintain the leg-rest in proper legsupporting position during the second motion phase.

It is the principal object of the present invention to provide a reclining chair of the type described having improved control means for providing the necessary movements of the seat and leg-rest during both motion phases, which control means are simple in construction and require few operating parts so that they [are economical in manufacture and subject to a minimum of operating defects.

A further object of the invention is the provision of a double movement chair incorporating control means oi the character described which operates to produce very little tilting movement of the seat during the first motion phase and to produce an appreciable tilting of the seat during the second motion phase.

In accordance with the invention, the seat control means includes front and rear guide links mountedion the chair support frame and connected to the seat, and a lost motion connection in the nature of a pin-and-slot coupling connecting the seat to the hack-rest for rearward movement of the seat when the back-rest is pivoted rearwardly. The guide links are so arranged as to raise the seat and maintain it in a substantially level position as it moves rearwardly during the first motion phase, and to incline the seat relatively sharply during the second motion phase. The pin-and-slot coupling provide a flexible connection between the seat and back-rest which permits these different movements of the seat during the two motion phases.

Additional objects and advantages of the invention will become apparent during the course of the following specification, when taken in connection with the accompanying drawings, in which:

FIG. 1 is a side elevational view, with parts broken away and shown in section, of a reclining chair made in accordance with the invention and shown in an upright sitting position with the leg-rest retracted;

FIG. 2 is a side elevataional view similar to FIG. 1, but showing the chair parts in an intermediate, tilted sit- 'ting position, with the leg-rest in extended, leg-supporting position;

FIG. 3 is a side elevational view similar to FIGS. 1 and 2, but illustrating the chair parts in their fully-reclined position;

FIG. 4 is a side elevational View, with parts broken 3,103,382 Patented Sept. 10, 1963 "ice 2 away and shown in section, of a reclining chair having a modified type of seat control structure madein accordance with the invention, this chair being shown in an upright sitting position with the leg-rest retracted;

FIG. 5 is a side elevational view of the chair illustrated in FIG. 4, with the chair shown in an intermediate tilted sitting with the leg-rest retracted; and

FIG. 6 is a side elevational view similar to FIGS. 4 and 5, but showing the chair thereof in a fully-reclined position.

Referring in detail to the drawings, and in particular to FIG. 1, the reclining chair shown therein includes a support frame designated generally by the reference numeral 10, and having a pair of spaced side walls 12 and 14 connected by cross bars or braces 16, 18 and 20. The support frame 10 is supported above the floor surfiace by (the usual legs 22.

The chair construction also includes a body-supporting structure designated :by reference numeral 24 and comprising a back-rest 26 and a seat 28. The back-rest 26 has a depending extension bar 30 rigidly connected thereto and mounted at its lower end on the support frame ll by pivot 32. A bar 34 is aifixed along the lower end of the seat 28 and projects from the rear end thereof, the projecting rear end of the bar 34 being connected by pivot pin 36 to the back-rest extension bar 30. The pivot pin 36 extends slidably within a longitudinal slot 38 in the black-rest extension bar 30 to provide a sliding connection for a purpose which will be presently described.

It will be appreciated that the back-rest 26 may :be

rearwardly with it during such rearward pivotal movement through the pin-and-slot coupling 36, 38. Seat control means are provided to support and guide the seat 28 during such rearward movement and to incline the seat.

The seat control means includes a front guide link 40 and a rear guide link 42 respectively mounted at spaced apart points on the support frame 10 by respective pivots 44 and 46. The upper end of the front guide link 40 is connected by pivot 48 to the forward portion of the seat 28, while the rear guide link 42 is connected by pivot 50 to the rear portion of the seat. The front guide link 40 is of appreciably greater length than the rear guide link 42.

In the sitting position shown in FIG. 1, the seat 28 is in a substantially level or horizontal attitude while the back-rest 26 is in a substantially upright attitude. The seat 28 rests upon and is supported by the cross-bar 18. The guide links 40 and 42 are inclined upwardly and forwardly from their pivotal mounts 44 and 46 toward the seat 28. In this position, the pin 36, carried by the seat bar 34, is located at the lower end of the slot 38.

When the occupant of the chair Wishes to assume a more comfortable position, he leans rearwardly about the hack-rest 26, causing the latter to turn about its pivotal mount 32 on the support frame 10'. The seat 28 is drawn rearwardly with the back-rest, and the guide links 4tl' and 42 turn rearwardly about their pivotal mounts 44 and 46. During the rearward pivotal movement of the guide links, their upper ends, carrying the respective pivots 48 and '50, move upwardly so that the seat 28 is raised thereby. Since both guide links 40 and 42 pivot upwardly during this first motion phase, the seat 28 is raised at its rear end as well as at its front end and is only slightly tilted in the intermediate, tilted sitting position of FIG. 2. As the rear end of the seat 28 is raised relative to the backrest 26, the pin 36 slides upwardly to the top of slot 38, increasing the effective length of the back-rest extention bar 30 between the pivot 36 and the fixed pivotal mount 32.

If the occupant of the chair in the intermediate, tilted sitting position of FIG. 2 wishes to assume a more cornfortable rec-lining position for greater relaxation he need only apply further rearward pressure against the backrest 26. The back-rest and seat will then move through various reclining positions to the fully-reclined position of FIG. 3. During the second motion ph ase, the front portion of the seat 28 is raised appreciably relative to the rear portion thereof, so that the seat is rearwardly inclined. The pin 36 remains at the top end of the slot 38 so that movement of the seat is wholly controlled by the guide links 40 and 42.

During the second motion phase, the seat 28 is drawn rearwardly with the back-rest 26 through the pin 36 which is now an immovable pivot relative to said back-rest. The front guide link 40 is still forwardly inclined and therefore turns upwardly and rearwardly, further raising the forward end of the seat 28. The rear guide link 42, however, is almost in a vertical position at the intermediate, tilted sitting position of FIG. 2, so that early in the second motion phase it passes through a vertical dead-center position and begins to pivot downwardly, lowering the rear end portion of the seat. Thus, the raising action of the front guide link 4t} and the lowering action of the rear guide link 4-2 combine to incline the seat 28 in the fully-reclined position of FIG. 3. It will be appreciated that the rear guide link 42, during the second mo tion phase, serves to maintain the pivot pin 36 at the upper end of slot 38, permitting the front guide link 44} to guide the seat 23 and produce a greater inclination thereof.

The seat control means also includes releasable stop means, generally indicated by reference numeral 89, for halting the movement of the body-supporting structure 24 in each of its three operative positions. The stop means 89 comprises an extension 40a of the front guide link 40 which projects beyond its pivotal mount 44 on the support frame 1t), and an arcuately-slraped bar 90 mounted at one end on the support frame ltl by pivot 91. The other free end of the bar 90 is connected to a spring 94 which is anchored on the support frame it) in such a manner that the free end of bar 90 is urged upwardly. The bar 90 has on its upper surface three notches 92 which correspond to the three operative positions of the body-supporting unit, as will presently be described. The free end of the front guide link extension 461: carries roller 93 which is sized to seat in each of the three notches 92.

The notches 92 are so positioned that in the upright sitting position of FIG. 1 the roller 93 is seated in the rearmost notch 92, the tension of spring 94 maintaining this seated engagement. When the body-supporting unit 24 is then moved toward the intermediate, tilted sitting position of FIG. 2, the arcu'ate bar 90 yields against spring tension, and the roller 93 moves into seated engagement with the center notch 3 2., As the roller 3 enters the central notch 92, under the biasing force of spring 94, this engagement interrupts the smooth movement of the body-supporting unit 24 and temporarily halts the latter in the intermediate, tilted sitting position of FIG. 2. When the body-supporting unit is then moved to the fully-reclined position of FIG. 3, the bar 90 again yields to permit the roller 93 to move to the forward notch 2.

The fully-reclined position of FIG. 3 is determined by engagement of the front guide link 4% with the cross-bar 18. It will be observed that in this position, the front guide link 4t} has assumed a vertical attitude, and that the forward end of seat 28 is raised to its fullest extent.

The chair also includes a leg-rest 80 and a leg-rest control linkage, designated generally by reference nu.- meral 52, for moving the leg-rest between the retracted position shown in FIG. 1 and various extended, legsupporting positions;

This control link-age 52 comprises a first pair of links 54 and 56 depending from the forward portion of the seat 23 and connected at spaced points thereon by respective pivots 53 and so, and a second pair of links 62 and 6% connected to spaced points on the leg rest by respective pivots 66 and 68. The free end of link 54 is connected by pivot '70 to the free end of link 62, while the links 56 and 6 2 are connected end-to-end by pivot 72. The link 54 crosses over the link 64 and is connected thereto at the crossing-over point by a pivot '74 so that movement of the link pairs is coordinated.

The leg-rest control linkage 52 is driven by an actuating link 76, the forward end of which is connected by pivot 82 to the upper portion of link '56. The rear end of actuating link 76 is mounted by pivot 78 on the support frame It).

When the seat 28 is moved rearwardly during the first motion phase, the leg-rest control linkage 52 is drawn rearwardly with the seat through the pivots 58 and 60. The actuating link '76, however, being mounted on the support frame 10, has no rearward movement. The 'actuating link 76 therefore pushes forwardly on the rearwardly-moving link 56 and causes the links 54 and 56 to turn forwardly about pivots 58 and 60 to expand the leg-rest control linkage 52 and carry the leg-rest 80 to the extended position shown in FIG. 2, in which said leg-rest is located substantially at the level of the forward end of the seat 28 land in position to receive and support the outstretched legs of the chair occupant.

It will be observed that in the intermediate, tilted sitting position of FIG. 2, the back-rest 26 is slightly reclined and the seat 28 is slightly inclined, so that while the occupants body is more relaxed, it is still in a forwardly-facing, substantially upright attitude suitable for reading, talking, viewing television or the like. The legrest 8%, however, is extended to a leg-supporting position.

During the second motion phase, as the leg-rest control linkage 52 is drawn reanwardly and upwardly with the seat, the actuating link 76 pivots upwardly but still exerts a pushing force on the rearwardly-moving link 56, causing the leg-rest 80 to be raised further to the extended position shown in FIG. 3. The leg-rest S0 is again at the level of the forward end of the seat 23 and is properly aligned with the body supporting plane provided by the reclined back-rest and inclined seat.

To bring the chair parts back to the sitting position, the occupant merely shifts his Weight forwardly and applies downward pressure on the extended leg-rest. The parts then move through intermediate tilted sit-ting position and the action of the control means is reversed to bring the body-supporting structure back to the upright sitting position of FIG. 1.

FIGS. 4-6 illustrate a reclining chair incorporating a modification in the seat control means. In this chair, like reference numerals are used for similar parts except that in this embodiment, the reference numerals form part of a series.

Referring in detail to FIG. 4, the reclining chair shown therein again includes a support frame designated generally by the reference numeral having a pair of spaced side walls 112 and 114 connected by cross bars 116, 118 and 12%, and supported above the floor surface by legs 122.

The chair of FIG. 4 also includes a body-supporting structure designated by reference numeral 124 and comprising a back-rest 126 and a seat 128. A depending extension bar 13%, carried by the back-rest 126, is mounted at its lower end on the support frame 110 by pivot 132. A bar 134 is affixed along the lower end of the seat 128 and projects from the rear end thereof. The projecting rear end of the bar 134- carries a pivot pin 136 which extends slidably within a longitudinal slot 138 in the back-rest extension bar to provide a sliding connection between the seat 128 and back-rest 126.

When the back-rest 12s is turned rearwardly about its pivotal mount 13-2 on the support frame 110, it draws the seat 128 rearwardly with it through the pin-and-slot coupling 136, 138. Seat control means are provided to support and guide the seat during such rearward movement and to incline the seat.

The seat control means includes a front guide link 140 mounted on the support frame 111} by pivot 144. The upper end of the front guide link 140 is connected by pivot 148 to the forward portion of the seat 128.

The sea-t control means also includes a rear guide link 148 which is of different construction than the rear guide link '48 shown in FIGS. l-3 and previously described. The rear guide link 148 is formed of two link parts or sections 184 and 18 6 connected in end-to-end elationship by pivot 188. The free end of link. section 186 is mounted on the support frame 110 by pivot 146, while the free end of link section 184 is connected to the rear portion of the seat 128 by pi-vo-t 150. The link section 184 has an integral transversely projecting flange 189 arranged at an angle of approximately 45 to the longitudinal axis of link section 184.

In the sitting position shown in FIG. 4, the seat 128 is in a substantially level or horizontal attitude while the back-rest 126 is in a substantially upright attitude. The seat 128 rests upon and is supported by the cross-bar 118. The front guide link 140 is inclined upwardly and forwardly from its pivotal mount 144 toward the seat 128. The sections 184- and 186 of the rear guide link are arranged angularly to each other, the rear section 186 extending horizontally and forwardly from its pivotal mount 146, and the front section 184 extending upwardly and forwardly from pivot 18-8 toward the seat 128. The rear section 186 rests upon and is supported by the rear crossbar 120. In this embodiment, the pin 136, carried by the seat bar 134, is located at the upper end of the slot 138 in the sitting position instead of at the lower end of the slot as in the embodiment of FIGS. 1-3.

When the occupant of the chair wishes to assume a more comfortable position, he leans rearwardly about the back-rest 126, causing the latter to turn about its pivotal mount 132 on the support frame 110. The seat 128 is drawn rearwardly with the back-rest, and the guide link 1461 and rear guide link section 184 turn rearwardly about their pivotal mounts 144 and 188. The other rear guide link section 186 remains immovable resting on cross-bar 129 so that during this movement, the pivot 188 is a fixed pivot. During this rearward pivotal movement of the guide link 140- and the link section 184, their upper ends, carrying the respective pivots .148 and 150, move upwardly so that the seat 128 is raised thereby. Movement of the rear guide link section 184 is halted at the end of the first motion phase by engagement of the flange 189 with the stationary link section 186, thereby temporarily retaining the body-supporting unit 124 in the intermediate, tilted sitting position of FIG. 5. In this embodiment, the short length of link section 184 causes the rear end of the seat 128 to be lowered relative to the back-rest 126, the pin 136 sliding downwardly to the bottom of slot 13-8 and decreasing the effective length of the back-rest extension bar 130 between the pivot 136 and the fixed pivotal mount 132.

If the occupant of the chair in the intermediate, tilted position of FIG. wishes to assume a more comfortable reclining position for greater relaxation applies further rearward pressure against the back-rest 126, causing the back-rest and seat to move through various reclining positions to the fully-reclined position of FIG. 6. During this second motion phase, the front portion of the seat 128 is raised appreciably relative to the rear portion thereof, so that the seat is rearwardly inclined. The pin 13-6 remains at the bottom end of the slot 138.

During the second motion phase, the seat 128 is drawn rearwardly with the back-rest 126 through the pin 136 which is now an immovable pivot relative to said back-rest. The front guide link 140 is still for- Wardly inclined and therefore turns upwardly and rearwardly, further raising the forward end of the seat 128. The section 184 of the rear guide link 142, however, is now rigidly coupled to the other link section 186 by the flange 189, and the two sections 184 and 186 turn as a unit about the fixed pivot 146. The rear guide link section 186 therefore rises from the cross-bar 120 during the second motion phase. Thus, the raising action of the relatively long front guide link 140 and the lowering action of the short rear guide =link sections 184, 186 combine to incline the seat 128- in the fully-reclined position of FIG. 6.

The fully-reclined position of FIG. 6 is determined by engagement of the front guide link 140 with the cross-bar 118. It will be observed that in this position, the front guide link 140 has assumed a vertical disposition, and that the forward end of seat 128 is raised to its fullest extent.

The chair also includes a leg-rest 180 and a leg-rest control linkage designated generally by reference numeral152, for moving the leg-rest between the retracted position shown in FIG. 4 and various extended, legsupporting positions. The leg-rest and its control linkage are substantially identical to those shown in FIGS. 13.

This control linkage 152 comprises a first pair of links 154 and 156 depending from the forward portion of the seat 128 and connected at spaced points thereon by re- A spective pivots 158 and 160, and a second pair of links vrest 180 by respective pivots 166 and 168.

162 and 164 connected to spaced points on the leg- The free end of the link 154 is connected by pivot to the free end of link 162, while the ends of links 156 and 164 are connected by pivot 172. The link 1154 crosses over the link 164 and is connected thereto at the crossing-over point by a pivot 174 so that movement of the link pairs is coordinated.

The leg-rest control linkage 152 is driven by an actuating link 176, the forward end of which is connected by pivot 182 to the upper portion of link 156. The rear end of actuating link 176 is mounted by pivot 178 on the support frame 110.

When the seat 128 is moved rearwardly during the first motion phase, the leg-rest control linkage 152. is drawn rearwardly with the seat through the pivots 158 and 160. The actuating link 176, however, having no rearward movement, pushes forwardly on the rearwardlymoving link 156 and causes the links 154 and 156 to turn forwardly about pivots 158 and 160 to expand the leg-rest control linkageand carry the leg-rest 180 to the extended position shown in FIG. 5, in which said legrest is located substantially at the level of the forward end of the seat and in position to receive and support the outstretched legs of the chair occupant.

During the second motion phase, as the leg-rest control linkage 152 is drawn rearwardly and upwardly with the seat, the actuating link 176 pivots upwardly but still exerts a pushing force on the rearwardly-moving links 156, causing the leg-rest 180 to be raised further to the extended position shown in FIG. 6. The leg-rest 180 is again at the level of the forward end of the seat and is properly aligned with the body-supporting planes provided by the reclined back-rest and inclined seat.

While preferred embodiments of the invention have been shown and described herein, it is obvious that numerous omissions, changes and additions may be made in such embodiments without departing from the spirit and scope of the invention.

What I claim is:

1. In a reclining chair comprising a support frame, a back-rest, a fixed pivot mounting the back-rest on the support frame for rearward pivotal movement, a seat, and coupling means connecting the seat to said backrest above the pivotal mount of the back-rest on the sup port frame for rearward movement of the seat when the back-rest is pivoted rearwardly, seat control means for guiding the seat through a first motion phase from a substantially level sitting position to an intermediate inclined position and through a second motion phase to a fully-inclined position, said seat control means including front and rear guide links pivotally mounted on the support frame and pivotally connected to spaced points on the seat, said front guide link being longer than the rear guide link and both guide links being inclined upwardly and forwardly from their pivotal mounts toward the seat in the sitting position, said guide links pivoting rearwardly and upwardly during the first motion phase to raise both the front and rear ends of the seat, the rear guide link being arranged to pass a vertical position and pivot downwardly and rearwardly during the second motion phase whereby to lower the rear end of the seat, the coupling means connecting the seat to the back-rest comprising a pin-and-slot lost motion connecting operable to permit the rear end of the seat to rise relative to the back-rest during the first motion phase, with the pin moving from end of the slot to the other end thereof, the pin engaging said other end of the slot during the second motion phase to provide a stationary pivotal connection between the seat and the back-rest.

2. Seat control means according to claim 1 in which said pin-and-slot coupling comprises a pin, rigid with the seat and a longitudinal slot in the back-rest, the pin being located at the lower end portion of the slot in the sitting position, sliding upwardly to the upper end portion of the slot during the first motion phase, and remaining in the upper end portion of the slot during the second motion phase.

3. In a reclining chair comprising a support frame, a back-rest having a depending extension, a fixed pivot mounting said back-rest extension on the support frame for rearward pivotal movement of the back-rest, a seat,

and coupling means connecting the seat to said back-rest above the pivotal mount of the back-rest on the support frame for rearward movement of the seat when the backrest is pivoted rearwardly, seat control means for guiding the seat through a first motion phase from a substantially level sitting position to a slightly inclined position and through a second motion phase to a further inclined position, said seat control means including front and rear guide links pivotally mounted on the support frame and pivotally connected to spaced points on the seat, said front guide link being arranged to raise the front end of the seat during both said motion phases, the rear guide link being arranged to move the rear end of the seat vertically relative to the back-rest during the first motion phase, said coupling means comprising a pin-and-slot connection between the seat and the back-rest, the pin moving from one end of the slot to the other end thereof during the first motion phase to permit the rear end of the seat to move vertically relative to the back-rest during the first motion phase, the pin engaging said other end of the slot during the second motion phase to provide a stationary pivotal connection between the seat and the back-rest, whereby the effective length of the back-rest extension between the pivotal mount of the back-rest and said coupling means is varied in the two motion phases.

References Cited in the file of this patent UNITED STATES PATENTS Schliephacke June 14, 1960 

1. IN A RECLINING CHAIR COMPRISING A SUPPORT FRAME, A BACK-REST, A FIXED PIVOT MOUNTING THE BACK-REST ON THE SUPPORT FRAME FOR REARWARD PIVOTAL MOVEMENT, A SEAT, AND COUPLING MEANS CONNECTING THE SEAT TO SAID BACKREST ABOVE THE PIVOTAL MOUNT OF THE BACK-REST ON THE SUPPORT FRAME FOR REARWARD MOVEMENT OF THE SEAT WHEN THE BACK-REST IS PIVOTED REARWARDLY, SEAT CONTROL MEANS FOR GUIDING THE SEAT THROUGH A FIRST MOTION PHASE FROM A SUBSTANTIALLY LEVEL SITTING POSITION TO AN INTERMEDIATE INCLINED POSITION AND THROUGH A SECOND MOTION PHASE TO A FULLY-INCLINED POSITION, SAID SEAT CONTROL MEANS INCLUDING FRONT AND REAR GUIDE LINKS PIVOTALLY MOUNTED ON THE SUPPORT FRAME AND PIVOTALLY CONNECTED TO SPACED POINTS ON THE SEAT, SAID FRONT GUIDE LINK BEING LONGER THAN THE REAR GUIDE LINK AND BOTH GUIDE LINKS BEING INCLINED UPWARDLY AND FORWARDLY FROM THEIR PIVOTAL MOUNTS TOWARD THE SEAT IN THE SITTING POSITION, SAID GUIDE LINKS PIVOTING REARWARDLY AND UPWARDLY DURING THE FIRST MOTION PHASE TO RAISE BOTH THE FRONT AND REAR ENDS OF THE SEAT, THE REAR GUIDE LINK BEING ARRANGED TO PASS A VERTICAL POSITION AND PIVOT DOWNWARDLY AND REARWARDLY DURING THE SECOND MOTION PHASE WHEREBY TO LOWER THE REAR END OF THE SEAT, TION PHASE WHEREBY TO LOWER THE REAR END OF THE SEAT, THE COUPLING MEANS CONNECTING THE SEAT TO THE BACK-REST COMPRISING A PIN-AND-SLOT LOST MOTION CONNECTING OPERABLE TO PERMIT THE REAR END OF THE SEAT TO RISE RELATIVE TO THE BACK-REST DURING THE FIRST MOTION PHASE, WITH THE PIN MOVING FROM END OF THE SLOT TO THE OTHER END THEREOF, THE PIN ENGAGING SAID OTHER END OF THE SLOT DURING THE SECOND MOTION PHASE TO PROVIDE A STATIONARY PIVOTAL CONNECTION BETWEEN THE SEAT AND THE BACK-REST. 